Just coincidentally, my in laws are going through a similar deal. Meme remembered that she had her grandpa's old gun in the closet. She comes out with a hatbox with an original Colt SAA. Built in 1888 in 32-20! And yes that is the same caliber as the 32 wcf.
I have no idea when yours was built or when 32-20 was offered in the Bisley. But I do recommend that you Do NOT refinish it! In fact, do not do anything to it at all. 32-20's were fairly rare and the only way to tell it's complete history is to get a written letter from Colt's. The fee is $200-$300 depending on the details of the gun, but this greatly enhances any collector value.
Go to this site as a starting place to get some information. I 'think'... and I am certainly no expert, that a Bisley in 32-20 was fairly rare, but any value determination greatly depends on it's age, which can be determined by it's serial number. To check general info of all kinds go to:
http://www.coltsaa.com/docs/info1st.htm#sn
You can also call Colt's at 1-800-962-COLT(2658), Monday through Friday 10am -12Noon and 1pm - 5pm EST. They can tell you by the serial number what year your gun was produced and you can go from there.
Just as a frame of reference, during my recent investigation of the family's heirloom, I have seen 1st gent SAA's in 32 WCF for as little as $1750 and Bisleys as high as $10,000!
The range is extraordinary and the most important thing to collectors is origniality (no refinshing, original stocks, all numbers match) and documentation - especially if it can be linked to a person who can be researched.
Don't even think about selling this wonderful find until you have done your homework.